In the electronic arts, printed circuit boards or printed wiring boards are configured to receive many electronic components, such as integrated circuit chips which may have memory or logic functions. Large memory capability requires a large number of integrated circuit chips. In modern technology, the integrated circuit chip packages are surface-mounted upon a printed circuit board. The printed circuitry is led to pads adjacent the edge of the board where interconnection to other circuitry is required. In the past, such boards have been permanently interconnected with the mother board by being soldered directly thereto. Connectors have more recently been employed to permit ease of insertion and removal of such boards. There are many contacts, and each contact requires wiping on installation in order to achieve reliable connection. With a large number of contacts, an adequate wiping force at each contact soon becomes too high so that excessive forces are required to install the board. These excessive forces may cause bending of the board, and with surface-mounted components, such bending is undesirable as causing connection failures.
Another problem which arises is the fact that these printed circuit boards, which are dielectric synthetic polymer composition material, often filled with fiberglass or the like, have a considerable thickness tolerance in normal manufacture. Thus, the board thickness varies to make it more difficult to achieve reliable contact. A prior edge connector employs a C-shaped stamped contact which permits low insertion force, but when a printed circuit board at the thickest end of acceptable tolerance is employed therein, the contacts are bent beyond the elastic limits so that they do not return to the prior unstressed condition when the board is removed. This does not permit reliable reuse of the connector. In addition, because the C-shaped contacts are stamped out of flat stock, they have a very high spring coefficient. When there is adequate contact force with the thinnest printed circuit board, then the contact force is too high with the thickest board, resulting in distortions and difficult installation.